Method of and apparatus for preparing paving compositions



1, 9 EB. CADWELL ETAL 2,015,707

METHOD OF AND A PEA RATUS FOR PREPARING PAVING COMPOSITIONS Fi le d Feb. 23, 1952 s Sheets- Sheet 1 .55 .50 {5'55 fig Z5 70 51 Q 7@) i7 14 15 q 5 41 12 fi wi u ATTORNEY Oct. 1, 1935 E. B. CADWELL ET AL 2,015,707

METHOD OF AND APPARATUS FOR PREPARING PAVING COMPOSITION Filed Feb. 23, 1932 s Sheets-Sheet 2 Oct. 1, 1935 E. B. YCADWELL 1-:r AL 2,015,707

METHOD OF AND APPARATUS FOR PREPARING PAVING COMPOSITIONS I I Filed Feb. 25, 1932 s Sheets-Sheet 3 um 76 iif: p a \k 7 INVE TORs M BY A'r'roRNEY Patented Oct. 1, 1935 warrior) or 'AND arrana'rus roa raaraamc PAVING comosrrrons Edwin n. Cadwell, Chicago, m., and Arthur B. Webb. Milwaukee, Wis.; said Webb assignor to said Cadwell Application February 23, 1932,.Serial No. 594,406

19 Claims. (Cl. 94-44) Our invention relates to methods and'means for preparing road paving compositions on the surface of the roadway to secure proper mixture and even coating of aggregate particles withv a binder material.

The-object of our invention is to provide a method which will be-more efficient and more economical of time, labor and materials than processes heretofore used, and to provide an apparatus which will facilitate the employment of our improved method.

Our method is an improvement upon a process now in common use in which the loose aggregate for the paving composition, together with a suitable quantity of binder material, is piled'in the roadway, preferably in a long pile extending longitudinally of the road, the pile measuring about six to eight feet wide and six to ten inches deep. Such piles are commonly created by first arranging the aggregate materials and then distributing the binder over them in liquid form. The aggregate may consist of variously sized stone, crushed rock, sand or other suitable material,

. and the binder employed may be any of the usual binders, such as tar, asphalt or bitumen.

The materials thus arranged are then worked together to secure an even coating of the binder over the surfaces of the aggregate particles, so that when the mixture is finally spread in place to provide a pavement, the particles will not disintegrate but will be firmly bound together.

This mixing and coating treatment has heretofore been accomplished by scraping or rolling the material over the surface of the roadway in a mass with a horizontal bladed implement inclined transversely of the road and moved continuously in a longitudinal direction, its forward end engaging the pile. In this manner, material is scraped from the pile and moved transversely of the road in advance of the blade and comes to rest again in a windrow-like pile parallel to the pile originally formed.

During the period of their movement, a portion of such aggregate particles as may have become method, which consists in scraping or rolling the material over the road surface as heretofore while at the same time violently, rapidly and repeatedly beating and rending the mass in the course of its movement.

This additional treatment of the material obtains a more complete disintegration of the lumps and amore even and thorough coating of binder over the particles of aggregate. We have found that this is more particularly true if the beating 10 and rending is performed in a rapid whirling and slashing manner, thus imparting a rotary or spiral movement to the constituents of the mass, causing them to be violently rubbed together under pressure and hurled one against the other and against the surface of the roadway.

In addition to the economies in time and labor eflected by our'improvement, there is a decided saving in material where cut-back asphalt or bitumen is employed as a binder for the reason that the volatile liquids used to cut the binder are quite expensive and as more time is taken to v process the mixtures, more of this liquid must be used to keep the binder fluid until the aggregate is thoroughly coated and the pavement finally laid.

To implement our improved process, we have provided the novel machine illustrated in the accompanying drawings of which the following is a detailed specification:

Fig. 1 is a side elevational view in section of our machine connected to the forward end of a conventional motor truck, the truck being shown with the near front wheel removed to reveal the disposition of the connecting elements.

Fig. 2 is a plan view taken on lines 2-! of Fig. 1.

Fig. 3 shows a front elevation of the machine with the apron broken away to reveal the disposiv tion of the mixingblades.

Fig. 4 is a perspective drawing of the frame assembly, by means of which the machine is at-. 40 tached to the truck frame.

Fig. 5 is a sectional view of the bevel-geared power-take-off assembly. taken on lines 5-5 of Fig. 3. v

Fig. 6 is a sectional view taken on lines 6-4 of Fig. 2 and shows the reducing gear transmission and sprocket chain drive.

Fig. '7 is an end view showing a modification of our machine.

Ill-l0 indicate the road engagin supports for our machine which are here shown as oblong shoes having their long dimensions extending parallel in the direction in which the machine is adapted to be moved, indicated by the arrow in Fig. 1. ll. indicates a base plate transversely mounted on the supports ID at an angle thereto.

On this base plate is a horizontal semi-cylindrical drum I2, one edge of which is disposed at its bottom and fixed parallel to the forward edge of the base plate by welding or other suitable means. This drum I2 constitutes the body portion of our apparatus and is closed at its forward end by a wall I3. A forwardly and outwardly curved wall I3 is supported in advance of the end wall I3 to provide a scoop capable of delivering material into the drum I2 adjacent its closed end.

Fixed on top of the drum is a parallel bar It strapped in position by a sheet metal strip. I 5 riveted or welded to the drum and formed. as illustrated. Depending from this bar at the rear" end of the drum is a bracket I6 carrying a bearing I! in which is rotatably supported one end of a shaft l8 extending centrally-thru the drum I2. The opposite end of the rotatable shaft I8 extends thru an opening in the scoop wall I3 and is rotatably supported in the lower portion of a cast metal gear casing l9, supported on the adjacent end of bar I4.

The rotatable shaft I8 is provided with a plurality of radially disposed mixing blades 20 etc.,'which extend a distance somewhat shorter than the radius of the drum I2, to provide a rotary beater and the shaft has a sprocket gear An apron 33 is attached in swinging relation 2I keyed to its forwardend within the casing I9. In the upper portion of the casing is a train of reduction gears, shown in Fig. 6. 22 is a short driving shaft journalled in the casing wall and extending externally-of the casing. Keyed on this shaft within the casing is a pinion gear 23 l meshing with an internal gear 24 keyed to shaft 25 which is similarly iournalledin the wall of the casing. Driven on this shaft 25 is also a spur toothed gear 23 in driving engagement with a smaller spur toothed gear 21 keyed to shaft 28 which carries a sprocket 23. A roller drive chain 30 couples the sprocket 29 to sprocket 2| to complete the drive from shaft 22 to the driven shaft [8, as will be readily understood. A propeller shaft 3| is coupled to the external end of shaft 22 by a conventional type of universal joint 32.

parallel along the upper edge of the drum I2 by means'of hinges 34 and is adapted to be held in any one of several adjusted positions by means of bracket 35 fixed on the apron; bracket 36 fixed on the drum and bar 31, as will be readily understood.

.The apparatus thus far described comprises a unit embodying all the dominant features of a machine which, together with our improved method, constitutes our present invention. The unit is operated by propelling it over the surface of the roadway in the direction indicated by the arrow in Fig. 1, its forward end in engagement with a pile of material to be mixed, and the shaft 3] is rotated at high speed to turn the train of gears and rapidly revolve shaft l8 carrying the blades-20-20 in a forward direction. We have found that best results are obtained in theusual work when the shaft I8 is rotated at a speed of approximately 175 R. P. M.

As the forward movement continues, the material engaged-by the scoop I3 is moved transversely by the inclined drum thru the paths of the rapidly revolving blades 20" which resist transverse movement of the material thru the drum and create a high pressure in the mass to more rapidly and evenly coat the aggregate particles with the binder material. The material ultimately again deposited on the road surface- .engaged by the rotating blades and theforwa-rd 10 moving lower edge of the drum and again hurled against the'road sin-face, and the treatment is repeated until it has passed completely across. the machine and isdeposited as heretofore described. 1

The blades 20-20 are shown to be straight but they may be pitched to deflect the material transversely inleither direction, if desired, and thus permit the drum to be disposed at any angle to the road. We have found it more economical, 20 however, to transversely move the material by obliquely disposing the drum as shown and that approximately thirty degrees of angular inclination is best suited.

In these repeated treatments of the material, the adjustable apron 33 serves importantly to regulate the distance which the material is thrown in advance of the apparatus. When the apron is positioned highly tilted (as shown in dotted lines in Fig. 6) the material is tangentially re- 0 leased from the drum at a point which allows it to be thrown a considerable distance by the blades, and since the direction of throw is oblique to the direction 'in which the apparatus is propelled, because of the inclination of the apparatus, the material is engaged only a few times in the course of its transverse movement.

Conversely, when the apron is positioned as shown in full lines in Fig.6, the material is hurled against the road surface immediately in advance of the apparatus and is resubjected to the treatment of the blades many times before it is finally deposited at rest by the rear end of the drum. Thus it will be seen that the adJustable apron functions to provide a high degree of flexibility,

permitting economical treatment of different mixtures requiring various processing. When the material requires. but little treatment, the apron is swung up and a deep cut is made by the scoop I3. When more processing is required, the apron is lowered and a cut of proportionately reduced depth is taken by the scoop. In either case, the same pressure may be built up and maintained within the drum without varying the forward speed, the speed of the shaft I8, the angular inclination of the apparatus or the pitch of the blades 20. This pressure is desirable in securing a proper amount of rubbing friction between the aggregate particles to secure a thorough coating of them by the liquid binder. I The modification illustrated in'Fig. 7 is particularly designed for use where the material to be mixed comprises very fine aggregate, such as clay or soft sand and is disposed and operated in an identical manner to the unit just described. In this modification the drum iselevated somewhat from the road surface and is open for-' wardly of its top rather than at its bottom.

Welded to the forward edge of the drum 90 and extending parallel thereto is a curved blade 92, the lower edge of which is positioned in close proximity to the road surface where it is attached to and supported by base plate 93 having shoes on its underside. A rotatable shaft 95 is provided with blades 75 "-96 etc., inall respects similar to the shaftv Ii, Attached to the upper end of each of the upand is positioned in advance ofthe blade' 96. A similar shaft 81 provided with blades 98-" etc., is carried parallel in the drum 90. A roller drive chain 99 is employed to drive both shafts in the directionindicatedanda plate I00, downwardly curved at its forward edge, covers the top and a portion of the front of the apparatus as shown. 1

' In operation, the blades "whip the trans-o versely moving material upward over the surface of the blade 92 into the drum 9!! where it is -enis finally piled on-the road by the rearwardly inclined end of the apparatus.

Either apparatus may be forwardly propelled over the road by drawing or pushing it, or it may be attached to the rear or intermediate the length of the frame of any suitable carriage.

We prefer, however, to movably attach the machine in front of a truck or tractor in accordance with the same principles employed to attach snow plows, described in copending application of Arthur BrWebb, filed'October 31', 1931, and

bearing Serial No. 572,333. and more particularly as follows: w

longitudinally extending push frame members 40 are attached at their forward ends to base plate II and upwardly inclined struts ll-fl J 40 etc. are attached to said members and to the drum l2. The push frame members are tied together intermediatetheir length by bracesl2 42 etc., and are provided at their rearends with journal brackets 43.

Push frame supports "-44 and 45- -45 are securely fastened to the truck frame it: and-are joined at their lower ends by a-shaft ll which extends thru the journal brackets-43 to pivotally support the ends of the push frame members. Upright A-frames are oppositely disposed on each of the push frame members forward of the braces 42 and are tied together by a shaft 4: n v I method varies, depending upon the design of the engine. The several methods ".Ii' well known, r 'howeven-to those'en'gaged in hig'hway'work and "are the same'as those employed to connect rotary snowDlows-etc;

on which flanged rollers 49 are rotatablymount ed. The faces and inner flange walls of these angular uprights 50 securely attached tothe front end of the truck frame. These uprights are further secured and braced 'to the truck by 1 V V able by mea'ns'of'slee've 15 and operating to drive braces 52. 1 By this arrangement, the thrust of the moving truck. is exerted against the rollers II to propel the apparatus and since these rollers are located well in advance of and above the plane in which i the push frame pivots, the direction of thrust is downward as well as forward, thus operating to hold the apparatus attached to the forward end of the push frame in close contact with the road surface and resisting tendency for it to ride upwardly over loose material in its path.

In order that the truck may be used totransport the mixing apparatus at speeds higher. than would be practical with the apparatus riding on the road, we have provided a hoisting arrangement by means of which the mixer may be liftedclear of theroad surface and carried bythe truck.

- on the shaft 45.

rollers engage the adjacent faces ofeaci'r of the rights 50 are oppositely disposed rearwardly extending brackets 53 carryingbearings rotatably supporting a transverse shaft 54, team end of which a bevel gear 55 is afllxed. Also attached .-5 to the upright member adjacent gear 55 is a bracket arm 56 journalled to rotatably support ashaft 51 which extends within the truck cab. A hand wheel 50 is attached to the inner end of the shaftl'l and its outer end is provided with 10 a bevel pinion 59 meshing with gear 55.

Wire; ropes 60-60 each have an endisuitably anchored to the truck frame. 5l-6l and are looped about pulleys 62-62 rotatably mounted on shaft 48 from whence they extend upwardly 15 and are attached to the rotatable shaft 54.

It will now be seen that turning of the hand wheel 58 will cause rotation of the shaft 54, wind up the cables ",and lift. the forward end of 7 the-push frame together with the. mixing unit 2() attached-thereto, the push frame being pivoted It will also be noted that the a lower ends of the uprights ill are inclined forwardlylat an angle which permits the rollers ll to move rearwardly in contact with the up- 21 rights when they are hoisted upward with the pivoting push frame.

To hold the apparatus in hoisted'position, a ratchet gear 83, shown in dotted lines in Fig. 3,

is provided on the rotatable shaft 5t and is en- 31 used by a pawl pivoted on bracket 56. This 'pawl is manually actuatedrto lock and release the shaft by a rod extending into the truck cabasshown. While the principal object ;of the hoist is to 35 permit the apparatus'to be carried clear of the road surface by thetruck to permit rapid transportation when the mixer is not at work, the

hoist is also used to support the mixing appa ratus in close working proximity tothe road'surface when the surface is'sosoft that the shoes III of the mixer cannot'carry their load without The blades of the mixing apparatus may be driven by coupling theshaft-Sl to an engine 45,

mounted on the push framezor on the truck. I we prefer, however, to utilize for this purpose the same engine which drives the truck. 7 A

Referring to Fig. 5, 13 is a coupling membersecuredindriven relationto the forward end ofthe truckengine. The exact'methodof securing this 7 member to the engine is nothere shown as the Bolted some member 1: is aclutch 14 ohm;

shaft 16 which extends within thehousing formed 60 Lin the" lower end of the casting l2."'Ihe clutch and carries a bevel gear I! at its inner end.

I In mesh with gear I9 is a similar gear mounted on one end of a shaft II which is'supported in a race type bearing 82 journalled in the housing wall. The opposite end of shaft 8| extends externally 'of the housing and is coupled by a universal joint 83 to shaft 84. Fixed to the shaft 84 is one end of a sleeve I5 keyed to slidingly receive and drive the splined shaft 3| attached to the mixing unit, thus providing a flexible drive to 7'5 asheretofcre described.

The foregoing description taken in connection with the accomparwing drawings discloses the principles of an apparatus which will be readily understood by. those skilled in the art to which the invention appertains and comprises. what we now consider to be the best embodiment thereof.

.We desire to have it understood, however, that the machine shown is merely illustrative. and that suchjchanges may be made, when desired, as fall within the scope of the here appended claims.

. We claim:

' 1. In methods of preparing materials for road paving compositions in which the materials are moved over the surface of a roadway by scraping, that improvement which consists in violently mixing and beating the material 'as it is moved.

2. The method of preparing materials for road paving compositions consisting in arranging the materials on the surface-of a roadway in a pile extending longitudinally thereof, the moving material from the pile transversely over the road surface while simultaneously mixing and heating it;

. 3. The method of preparing materials for road paving compositions consisting in arranging the materials on the surface of a roadway in a pile fed thru the mixingapparatus.

extending longitudinally thereof, movingmaterial from the pile transversely over the road surface and repeatedly picking up portions of the material and violently hurling them against the road surface in the course of their transverse movement.

4. In methods of preparing materials for road mixed paving compositions in which the materials, comprising aggregate and a binder therefor, are moved transverselyover the road surface by scraping, that improvement which cohsists in partially confining the materials during their transverse movement and violently mixing and beating them while so confined to provide a more uniform mixture of the aggregate particles and a more perfect coating of binder material thereover.

5. In methods of preparing road mixed paving compositions, that improvement which consists in mixing-the materials by feeding them thru a drum type rotary mixing apparatus propelled on the roadway at an oblique angle in engagement with the materials, whereby the materials are 6. In methods of preparing materials for road paving compositions, that improvement which consists in propelling a mixing drum at an oblique angle in engagement with the materials, whereby the materials are fed transversely thru the drum, and slashing thru the materials in the course of their transverse movement thru the drum,

7. An apparatus for preparing road mixed paving compositions adaptedto be moved forwardly in engagement with material for mixture lying in its path comprising a horizontal drum extending transversely to the direction of movement, a rotary beater comprising a plurality of mixing blades supported in said drum; power means for driving said beater, and a scoop at one end of the drum arranged to engage the material and deliver it into the drum, the other end of the drum being open whereby it is adapted to deliver the mixed material onto the roadway. v

8. A portable apparatus for preparing road mixed paving compositions comprising a horizontal trough-shaped drum having one of its long edges disposed at its bottom, a rotary beater in said drum comprising a shaft and a plurality of mixing blades fixed on said shaft andpartly shrouded by said drum, and power means for rotatably driving said beater, the upper portion of said drum extending downwardly to shroud 5 said blades forward of said beater shaft.

9. A portablev apparatus for preparing road mixed paving compositions comprising a hurl-'- zontal trough-shaped drum having one of its long edges disposed at its bottom, a rotary beater in the drum comprising a shaft and a plurality of mixing blades fixed on said shaft and partly shrouded by said drum, an adjustable apron attached along the upper edge of the drum whereby said blades are shrouded forward of said heater l5 shaft, and power means for driving said heater.

10. An apparatus for preparing road mixed paving compositions comprising a horizontal trough-shaped drum having one of its long edges disposed at its bottom, said drum being adapted for forward movement in engagement with paving materials lying in its path and inclined obliquely to its direction of movement for transversely scraping the engaged materials over the road surface, a rotary beater comprising a plurality of mixing blades rotatably supported in said drum, and power means for driving said blades whereby they are caused to violently mix and beat the materials in the course of their transverse movement, the rearward end of said drum being open whereby it is adapted to deliver the mixed materials onto the roadway.

11. Apparatus for preparing materials for road paving compositions comprising, in combination, means for moving the materials transversely over the surface of a roadway, and a rotary mixer for mixing the materials as they are moved, said mixer comprising a shaft, a plurality of fiat blades attached thereto and arranged and adapted to be driven edgewise, and power means for 4 driving said mixer.

12. Apparatus for preparing road-mixed paving compositions adapted to be moved along a roadway, comprising a transverse rotary mixing device and a horizontal trough-shaped drum partially surrounding said device having its rearward edge close to the road surface, the drum extending forwardly across the top of said mixing device and downwardly and having its forward edge below the horizontal plane tangent with the top of the drum.

13. A portable apparatus for preparing roadmixed paving compositions comprising a horizontal-trough-shaped drum having one of its long edges disposed at its bottom, a rotary mixer 11x55 said drum comprising a shaft and a plurality of fiat blades attached to said shaft and arranged and adapted to be driven edgewise, and power meansfor driving said mixer.

14. A portable apparatus for preparing roadmixed paving compositions comprising a horizontal trough-shaped drum having one of its long edges disposed at its bottom, a rotarymixer in said drum comprising a shaft and a plurality of fiat blades attached to said shaft and arranged and adapted to-be driven edgewise and partly shrouded by said drum, and power means for driving said mixer, the upper portion of said drum extending downwardly to shroud said blades forward of said mixer shaft.

15, Apparatus for preparing road-mixed paving compositions adapted to be moved along a roadway, comprising a transverse rotary mixing device and" a horizontal trough-shaped drum partially surrounding said device and having its 7 1 ram combination. arnm i' rearward edge clcseto the road surface,

drum extending forwardly across; the top of'anddownwardly in front of said mixing device.

16. An apparatus for, preparing road mixed paving compositions adap wardly in engagement with material for mixture lying in its path comprising a horizontal troughshaped drum extendingtransversely'to the'direction of movement, a rotary beater comprising i a shaft having a plurality of blades fixed thereonwithin said drum, a'horizontal bladeat tached along the forward long'edge of the and curved-downwardly therefrom, a rotary beater comprising 8 1' mixing blades thereoiii z said blade. memsbfli fiitllifi W 894d am nes and power meansiforsrotatably driving the shaft. 1'1. In combination, 1 apparatus for preparing road mixedpaving compositionsadapted to be forwardly. moved in engagement with material for mixture lying on comprisinra horizontal trough-shaped drum having one of its long edges disposed at its bottom, an adjustable apron attached parallel along the upper edge of the drum, a heater comprising a plurality of mixing blades rotatably supported in the drum, and a scoop at one end of the drum engine mounted thereon,

arranged to engage the material and deliver it into the drum, the other end of said drum being open whereby it is adapted to deliver mixed maa carriage having an a frame connecting the apparatus to the carriage, and a driving connection coupling the engine to the mixing apparatus.

terial onto the roadway;

ted tobe moved for- .Jto the direction of movement, a heater compris-' f ing a plurality of mixing blades rotatably supported in said drum.

ha in i pl mmet pported' in "advance or e" and' forward of its shaft.

the surface of a roadway j-for mixture lying on the surface of a roadway comprising a horizontal drum obliquely inclined 5 and a scoop at the'forward end of the drum arranged to engage the material and deliver it intothe drum, the rear- 10 ward end .of the drum being open whereby it is -adapted to deliver the mixed material onto the roadway; a carriage havin ,thereon, aframe connecting the apparatus to an engine mounted the carriage and a driving connection coupling ehgine tothe'beater in driving relation. vI' 19. In combination, 1 road mixed paving compositions adapted to be apparatus for preparing forwardly moved on the surface of a roadway comprising a horizontal drum obliquely inclined to the direction of movement, a beater in said drum comprising a rotatable shaft and a pinrality of mixing blades fixed on said shaft and partly shrouded by said drum, the upper portion of said drum extending downwardly to shroud said blades forward of said beater shaft; a carriage having an engine mounted thereon, a rigid frame connecting said drum in movable relation to said carriage, a flexible driving connection coupling the engine to said rotatable shaft, and a hoist for elevating the apparatus in relation to the carriage.

EDWIN B. CADWELL.

ARTHUR B. WEBB. 

